1. Field of the Invention
The present invention relates to a robot hand of an automatic handling robot in a semiconductor manufacturing device or an inspection device to inspect semiconductor wafers in the manufacturing process thereof, etc., which is used for carrying semiconductor wafers from a wafer cassette to the devices.
2. Description of the Related Art
In a known robot hand of an automatic handling robot for carrying a wafer from a wafer cassette to an inspection device or the like, a mechanism in which a wafer is held by vacuum suction is adopted. The known holding mechanism is shown in FIGS. 3 and 4. Namely, a robot hand 1 is provided on its one end with a suction air intake 2, and on the other end thereof with a plurality of suction portions 3. A groove 4 for an air passage is provided to connect the suction air intake 2 with the suction portions 3 and to interconnect the suction portions 3. The groove 4 is covered by a cover 5 adhered thereto.
In use, the robot hand 1 is inserted in a gap of a predetermined pitch between adjacent wafers in the cassette to hold a wafer through the suction portion 3 due to vacuum suction and remove the wafer from the cassette. Thereafter, the robot hand 1 transfers the wafer to a wafer chuck portion of the inspection device or the like. The robot hand is inserted in a robot hand transferring/receiving recess formed on the wafer chuck portion to hold the wafer by the chuck portion due to vacuum suction. Consequently, the wafer is delivered from the robot hand. The robot hand is removed from the recess. Thus, the robot hand delivers the wafers from the cassette to the wafer chuck portion.
As described above, since it is necessary to insert the robot hand into the gap between the wafers in the cassette and into the robot hand transferring/receiving recess of the wafer chuck portion, the robot hand must be very thin, i.e., about 3 mm in thickness, and furthermore, a groove for air passage of not more than about 1 mm in depth must be provided. Consequently, the strength is reduced, so that the robot hand can be easily broken.
In recent years, the holding method of a wafer has been changed from a support at points to a support by a surface, in accordance with an increase in the diameter and the precision of a wafer. To prevent a wafer from being deformed, it is desirable to hold the wafer by as large a surface as possible. Consequently, it is difficult to form a wafer transferring/receiving recess whose width is large enough to transfer or receive the wafer in the wafer chuck portion, and hence the width of the robot hand must be made small. This also makes it difficult to obtain a rigid and sufficiently strong robot hand.